MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 31W (YUTU) WARNING NR 11// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUPER TYPHOON (STY) 31W (YUTU), LOCATED APPROXIMATELY 177 NM EAST OF ANDERSEN AFB, GUAM, HAS TRACKED NORTHWESTWARD AT 12 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS THE SYSTEM HAS MAINTAINED A WELL-DEFINED, ALBEIT SMALLER, 18-NM EYE AS FEEDER BANDS WRAPPED EVEN TIGHTER INTO A HIGHLY COMPACT, DEEP, AND MORE SYMMETRIC CENTRAL CONVECTION. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE EYE FEATURE THAT IS SPOT-ON WITH A MICROWAVE EYE IN THE 232335Z AMSU PASS AND LINED UP WELL WITH A CIRCULATION FEATURE IN A COMPOSITE RADAR LOOP FROM ANDERSEN AFB. THE INITIAL INTENSITY OF 130 KNOTS IS BASED ON EQUIVALENT AND NEARLY CONCENTRIC DVORAK ESTIMATE FIXES FROM PGTW AND RJTD OF T6.5/127 KNOTS AND REFLECTS THE CONTINUED RAPID INTENSIFICATION. UPPER LEVEL ANALYSIS INDICATES STY 31W IS IN A VERY FAVORABLE AREA WITH LOW (10-15 KNOT) VERTICAL WIND SHEAR (VWS) AND EXCELLENT RADIAL OUTFLOW WITH A STRONG POLEWARD BIAS. ADDITIONALLY, ALONG-TRACK SEA SURFACE TEMPERATURES (SST) AND OCEAN HEAT CONTENT (OHC) ARE HIGHLY CONDUCIVE. THE CYCLONE IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO THE NORTHEAST. 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. STY 31W IS EXPECTED TO TRACK WEST-NORTHWESTWARD UNDER THE STR THROUGHOUT THE FORECAST. ENVIRONMENTAL CONDITIONS WILL REMAIN FAVORABLE FOR CONTINUED INTENSIFICATION, ALBEIT AT A MORE GRADUAL RATE TO A PEAK OF 155 KNOTS BY TAU 72. NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT WITH MINIMAL SPREADING UP TO 240 NM BY TAU 72. A NOTABLE RIGHT OF ENVELOPE OUTLIER IS HWRF. THERE IS HIGH CONFIDENCE IN THIS PORTION OF THE JTWC TRACK FORECAST THAT IS LAID JUST LEFT OF CONSENSUS TO OFFSET THE UNLIKELY POLEWARD TRACK OFFERED BY HWRF. C. BEYOND TAU 72, STY YUTU WILL SLOW DOWN AS IT APPROACHES A COL AREA AHEAD OF A MIDLATITUDE TROUGH. VWS, SST, AND OHC VALUES WILL REMAIN FAVORABLE. HOWEVER, POLEWARD OUTFLOW WILL DIMINISH NEAR THE COL, RESULTING IN A SLIGHT WEAKENING TO 130 KNOTS BY TAU 120. THE NUMERICAL MODEL GUIDANCE SIGNIFICANTLY SPREADS OUT TO OVER 700 NM BY TAU 120 WITH CTCX AND NVGM ON THE RIGHT MARGIN OF THE ENVELOPE OFFERING A SHARP AND EARLY RECURVATURE AND EGRR AND AFUM ON THE LEFT MARGIN OFFERING A FLAT WESTWARD TRACK. IN VIEW OF THE WIDE SPREAD, THERE IS LOW CONFIDENCE IN THE EXTENDED PORTION OF THE JTWC TRACK FORECAST THAT IS LAID JUST LEFT OF AND SLOWER THAN CONSENSUS TO OFFSET THE UNLIKELY SHARP POLEWARD RECURVATURE OFFERED BY CTCX AND NVGM.//N NNNN NNNN